AMC has confirmed the news, with Slattery shooting his first episode in February -- though he'll be working on it far in advance.

"It takes a lot more time," to direct an episode than to act in one, he told The Hollywood Reporter. "You have a hand in the whole thing, and each one takes about a month, from a directorial standpoint. From the time you get the script to the time you turn your cut in, it’s a month. And it’s a long month."

The 50-year-old actor, who directed three episodes of "Mad Men" in the past, including Season 5's "Signal 30," will work alongside creator Matthew Weiner in order to keep the plot line a secret.

"You get [the script] a little in advance of when the actors get it, but only for the necessity of preproduction," Slatter explained. "And they used to try -- and they still do try -- to limit the amount you’re [acting] in it, but I think we’ve all kind of gotten a grip on what that’s like, so they don’t have to make as much of an effort. And so, yeah, you get what you get. Especially with us."

"Jon Hamm is directing as well, so we’re there," he added. "So our schedules are kind of easier for them to figure out because the other directors come in and out."